The overarching goal of this center application is to determine how marked reduction in the nicotine content of cigarettes impacts the use and effects of tobacco in current smokers. Reduction in nicotine content has been proposed as a potential regulatory measure to render cigarettes non-addictive and, consequently, to reduce smoke exposure and improve public health. Reducing nicotine content in cigarettes has become a possibility as a result of the passage of the Family Smoking Prevention and Tobacco Control Act (FSPTCA), which gives the Food and Drug Administration jurisdiction over tobacco products including the authority to reduce (but not ban) levels of nicotine in cigarettes. The proposed grant with its four inter-related projects, which cross disciplinary boundaries, will help to inform policy decisions. Project 1 includes two human studies evaluating the dose-response relationship for nicotine yield within the range thought to be at or below threshold for dependence and the potential use of concurrent nicotine replacement therapy (NRT) to facilitate the transition to VLNC cigarettes. Project 2 is a multi-site trial assessing the effects of prolonged use of VLNC in a large sample and comparing immediately switching to VLNC cigarettes to gradually reducing the nicotine content in cigarettes over a period of 20 weeks. Project 3 begins to address an important concern about the viability of a new standard for nicotine content in sub-populations (here we focus on smokers with schizophrenia) who might be particularly vulnerable to the effects of reduction in nicotine. Project 4 addresses concerns that the manipulation of other constituents in tobacco could offset the predicted gains of VLNC cigarettes by determining the relationship between the threshold dose for maintaining rat nicotine self-administration and the presence of minor alkaloids, beta-carbolines, acetaldehyde, and MAO inhibitors. The contribution of this Project to the overall center is Crucial. To accomplish these goals, we have proposed an Administrative Core (Core A), a Biomarkers Core (Core B), and a Biostatistics Core (Core C).